Structures or platforms which are positioned in a body of water, usually at an offshore location, are utilized for a number of functions. For one thing, they are used for drilling wells into the substrate beneath the structure to locate and produce hydrocarbons such as crude oil, gas and the like. These structures find use in virtually any depth of water. However, they are found to be most practical up to and including at least 1,000 feet of water.
Such structures are not only utilized for drilling new wells into a known hydrocarbon containing reservoir; they can also be used for the ancillary purpose of collecting hydrocarbons from a number of dispersed wells. Further, they find use as stations for treating the hydrocarbons before they are pipelined or shipped to a remote point.
In the instance of a platform utilized to gather or accumulate the production of a number of scattered wells, the platform normally contains equipment for initially treating the crude oil and/or the gas which is received. This treatment, although preliminary to the actual refining or storage steps, is such that the oil or gas is retained only provisionally before being passed on to a tanker or to an inshore pipeline.
When the platform is used as a gathering point for a number of dispersed wells, it is normally provided with a series of conductors which extend downwardly from the platform deck, and into the substrate. Thus, as the various pipelines are channeled into the offshore structure, they are connected with one of the latter's conductors whereby liquid crude, or gas can be pumped directly up into the platform's holding tanks.
These downwardly extending conductors from the deck serve a number of functions. They are used, for example, to conduct water and other fluids, as well as for enclosing electrical lines and cables which must extend from the platform deck to various well heads.
It is sometimes desirable to position the conductors internally of a platform leg since the latter would act as a natural support for the relatively small and fragile conductors. However, in that the conductors must eventually extend outwardly through the leg wall, it becomes necessary to form passages or openings for them to pass through.
One way of furnishing the leg with suitable accommodations, is to place them with diver assistance after the leg has been installed. Thus, during the installation of any offshore platform of the type under consideration, the piles or legs are individually driven in a generally upright position to a desired depth into the substrate. After the proper number of support piles or legs have been installed, the deck section is lowered into place and fastened.
In the presently disclosed arrangement, after the support piles have been forced into place, one or more of them are provided with an outer protective shield. The latter is lowered into place in such a manner that it will be properly positioned to engage ice or other floating objects regardless of the level of the water in response to tidal changes thereby to protect both the leg and the conductors.
In the disclosed arrangement, an offshore structure is provided which is normally installed in a body of water at an inland site or in a tidal area. The structure, as noted, can embody a deck or superstructure which holds means for drilling wells or for merely functioning to gather flows of oil, gas, or both from incoming pipelines and remote well heads.
The deck is supported beyond the surface of the water by at least one, and preferably a plurality of legs or piles. One or more of the latter carries an external sleeve in such a manner that floating objects, as they near the leg, will be contacted by the protective sleeve. Thus, neither the leg itself nor conductors which are disposed about the leg periphery will suffer damage.
It is therefore an object of the invention to provide a platform or offshore structure particularly adapted for use in an environment where ice is found to be prevalent for at least a part of the year. A further object is to provide a platform of the type contemplated which embodies external protection from floating material which might come into damaging contact with the platform support members. A still further object is to provide an offshore structure support leg which is particularly adapted to resist damage which might result through contact with floating objects or similar materials.